ROPS frame for work vehicle, and work vehicle

ABSTRACT

A ROPS frame for a work vehicle includes: a first pipe having an end; a second pipe having an end facing the end of the first pipe; a plate-shaped first joint coupled to the end of the first pipe and oriented orthogonally to a longitudinal direction of the pipes; a plate-shaped second joint coupled to the end of the second pipe and oriented orthogonally to the longitudinal direction of the pipes, the second joint being placed on the first joint; and a bolt extending through the first and second joints and fastening the first and second joints to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2021-153445 filed Sep. 21, 2021, the disclosure of which is herebyincorporated by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a ROPS frame for a work vehicle thatincludes a plurality of pipes. The present invention also relates to awork vehicle equipped with the ROPS frame.

2. Description of the Related Art

JP 2009-280090 A discloses a work vehicle and a ROPS frame includingbent pipes. Further, a relatively large work vehicle including frontseats and back seats, for example, may be provided with a ROPS frameincluding a plurality of pipes coupled to one another.

There has been a demand in relation to a ROPS frame including aplurality of pipes for a weight reduction at a portion at which therespective ends of a pair of pipes face each other and are coupled toeach other.

The present invention has an object of providing a ROPS frame for a workvehicle and a work vehicle with a reduced weight at a portion at whichthe respective ends of a pair of pipes face each other and are coupledto each other.

SUMMARY OF THE INVENTION

The present invention is a ROPS frame for a work vehicle, including: aplurality of pipes including: a first pipe having an end; and a secondpipe having an end facing the end of the first pipe; a plate-shapedfirst joint coupled to the end of the first pipe and orientedorthogonally to a longitudinal direction of the pipes; a plate-shapedsecond joint coupled to the end of the second pipe and orientedorthogonally to the longitudinal direction of the pipes, the secondjoint being placed on the first joint; and a bolt extending through thefirst and second joints and fastening the first and second joints toeach other.

The present invention is configured such that the first and secondjoints are placed on each other in such a manner that an end of thefirst pipe and an end of the second pipe face each other and that thefirst and second joints are provided with a bolt extending therethroughand fastening the first and second joints to each other. This allows therespective ends of the first and second pipes to be coupled to eachother with use of the first and second joints.

The present invention includes plate-shaped first and second joints tosimplify and reduce the weight of a portion at which the respective endsof the first and second pipes face each other and are coupled to eachother.

The present invention is a ROPS frame for a work vehicle, including: aplurality of pipes including: a first pipe having an end; and a secondpipe having an end facing the end of the first pipe; a plate-shapedfirst joint and a plate-shaped second joint each placed on an outersurface of the end of the first pipe and on an outer surface of the endof the second pipe and opposite to each other in a cross-sectional viewof the pipes; a first collar attached to an inner portion of the firstpipe which inner portion faces the first joint and to an inner portionof the first pipe which inner portion faces the second joint; a secondcollar attached to an inner portion of the second pipe which innerportion faces the first joint and to an inner portion of the second pipewhich inner portion faces the second joint; a first bolt extendingthrough the first and second joints and the first collar and fasteningthe first and second joints toward each other; and a second boltextending through the first and second joints and the second collar andfastening the first and second joints toward each other.

The present invention is configured as follows: With an end of the firstpipe facing an end of the second pipe, the first bolt extends throughand fastens to one another the end of the first pipe, the first andsecond joints, and the first collar to couple the first and secondjoints to the end of the first pipe.

Further, the second bolt extends through and fastens to one another theend of the second pipe, the first and second joints, and the secondcollar to couple the first and second joints to the end of the secondpipe.

The above configuration allows the respective ends of the first andsecond pipes to be coupled to each other with use of the first andsecond joints. Further, the first and second collars prevent the firstand second pipes from buckling as a result of the fastening by the firstand second bolts.

The present invention includes plate-shaped first and second joints tosimplify and reduce the weight of a portion at which the respective endsof the first and second pipes face each other and are coupled to eachother.

The present invention is a ROPS frame for a work vehicle, including: aplurality of pipes including: a first pipe having an end; and a secondpipe having an end facing the end of the first pipe; a plate-shapedjoint with: a first portion coupled to an inner surface of the end ofthe first pipe; and a second portion protruding from the end of thefirst pipe and disposed inside the end of the second pipe; a nut coupledto an inner surface of the second portion of the joint; and a boltscrewed in the nut from outward of the end of the second pipe andfastening the second pipe and the joint to each other.

The present invention is configured such that with an end of the firstpipe facing an end of the second pipe, the joint is inserted in the endof the second pipe, and the bolt extends through and fastens to oneanother the end of the second pipe, the joint, and the nut. This allowsthe respective ends of the first and second pipes to be coupled to eachother with use of the joint.

The present invention includes a plate-shaped joint to simplify andreduce the weight of a portion at which the respective ends of the firstand second pipes face each other and are coupled to each other.

The present invention may preferably further includes: a first framemember oriented in a direction crossing the first and second pipes andhaving an end facing the respective ends of the first and second pipes;and a coupling member coupled to the end of the first pipe and the endof the first frame member and coupled to the end of the second pipe andthe end of the first frame member.

A work vehicle may include a ROPS frame including first and second pipeswith respective ends facing each other and coupled to each other. Insuch a case, the ROPS frame may include a first frame member that isoriented in a direction crossing the first and second pipes and that hasan end facing the respective ends of the first and second pipes, and thefirst frame member may be coupled to the first and second pipes.

The above embodiment of the present invention includes a coupling membercoupled to the end of the first pipe and the end of the first framemember and coupled to the end of the second pipe and the end of thefirst frame member.

The above configuration allows the respective ends of the first andsecond pipes and the end of the first frame member to be coupled to oneanother with use of the coupling member. This allows the ROPS frame toadvantageously have an improved strength.

The present invention may preferably further includes: a second framemember oriented in a direction crossing the first and second pipes andthe first frame member and having an end facing the respective ends ofthe first and second pipes, wherein the coupling member is furthercoupled to the end of the first pipe and the end of the second framemember and coupled to the end of the second pipe and the end of thesecond frame member.

A work vehicle may include a ROPS frame including first and second pipesand a first frame member coupled to one another as described above. Insuch a case, the ROPS frame may include a second frame member that isoriented in a direction crossing the first and second pipes and thefirst frame member and that has an end facing the respective ends of thefirst and second pipes and the end of the first frame member, and thesecond frame member may be coupled to the first and second pipes.

The above embodiment of the present invention is configured such thatthe coupling member is not only coupled to the respective ends of thefirst and second pipes and the end of the first frame member, but alsocoupled to the end of the first pipe and the end of the second framemember and coupled to the end of the second pipe and the end of thesecond frame member.

The above configuration allows the respective ends of the first andsecond pipes and the respective ends of the first and second framemembers to be coupled to one another with use of the coupling member.This allows the ROPS frame to advantageously have an improved strength.

The above embodiment of the present invention is configured such thatthe coupling member functions not only to couple the respective ends ofthe first and second pipes and the end of the first frame member to oneanother, but also to couple the respective ends of the first and secondpipes and the end of the second frame member to one another. Thisadvantageously allows the coupling member to have a simple structure.

The present invention may preferably be arranged such that the end ofthe first frame member and the end of the second frame member arecoupled to each other.

The above embodiment of the present invention not only allows therespective ends of the first and second pipes and the respective ends ofthe first and second frame members to be coupled to one another with useof the coupling member, but also allows the respective ends of the firstand second frame members to be coupled to each other. This allows theROPS frame to advantageously have an improved strength.

The present invention may preferably be arranged such that the couplingmember is coupled to the end of the first pipe at a first couplingportion apart from a second coupling portion at which the couplingmember is coupled to the end of the second pipe, and the respective endsof the first and second pipes face each other at a portion between thefirst coupling portion and the second coupling portion.

The above embodiment of the present invention is configured as follows:In a case where the coupling member is coupled to the respective ends ofthe first and second pipes, the coupling member is coupled to the end ofthe first pipe at a first coupling portion apart from a second couplingportion at which the coupling member is coupled to the end of the secondpipe.

Further, the respective ends of the first and second pipes face eachother at a portion between the first coupling portion and the secondcoupling portion. This simple configuration prevents contact between thecoupling member and the portion at which the respective ends of thefirst and second pipes are coupled to each other.

The present invention may preferably be arranged such that the couplingmember is coupled to the end of the first pipe with: the coupling memberplaced on an outer surface of the end of the first pipe; and a firstauxiliary coupling member placed on the outer surface of the end of thefirst pipe and coupled to the coupling member, and the coupling memberis coupled to the end of the second pipe with: the coupling memberplaced on an outer surface of the end of the second pipe; and a secondauxiliary coupling member placed on the outer surface of the end of thesecond pipe and coupled to the coupling member.

The above embodiment of the present invention is configured such thatthe coupling member is coupled to the end of the first (second) pipe insuch a manner that the coupling member and the first (second) auxiliarycoupling member cover the end of the first (second) pipe.

The above configuration allows the coupling member to be coupled firmlyto the end of the first (second) pipe regardless of the cross-sectionalshape of the end of the first (second) pipe.

A work vehicle according to the present invention includes the ROPSframe.

The work vehicle according to the present invention, which includes aROPS frame that is simple and lightweight as described above, is alsolightweight accordingly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a left side view of a work vehicle.

FIG. 2 is a left side view of a ROPS frame.

FIG. 3 is a plan view of a ROPS frame.

FIG. 4 is a perspective view of a ROPS frame.

FIG. 5 is an exploded perspective view of a left-side portion of a ROPSframe.

FIG. 6 is an exploded perspective view of a right-side portion of a ROPSframe.

FIG. 7 is a plan cross-sectional view of a left-side front joint and itsnearby portion of a ROPS frame.

FIG. 8 is a cross-sectional view of the left-side front joint and itsnearby portion in FIG. 7 taken along line VIII-VIII in FIG. 7 .

FIG. 9 is an exploded perspective view of a left-side front joint andits nearby portion of a ROPS frame.

FIG. 10 is a plan cross-sectional view of a left-side rear joint and itsnearby portion of a ROPS frame.

FIG. 11 is a cross-sectional view of the left-side rear joint and itsnearby portion in FIG. 10 taken along line XI-XI in FIG. 10 .

FIG. 12 is an exploded perspective view of a right-side rear joint andits nearby portion of a ROPS frame.

FIG. 13 is a left side view of a portion and its nearby portion of aROPS frame at which the back upper end of a left pipe is coupled to thefront upper end of another left pipe.

FIG. 14 is a cross-sectional view of the portion and its nearby portionin FIG. 13 taken along line XIV-XIV in FIG. 13 .

FIG. 15 is a cross-sectional view of the portion and its nearby portionin FIG. 13 taken along line XV-XV in FIG. 13 .

FIG. 16 is a plan cross-sectional view of a portion and its nearbyportion of a ROPS frame at which the back upper end of a left pipe iscoupled to the front upper end of another left pipe.

FIG. 17 is a perspective view of a coupling member.

FIG. 18 is a side cross-sectional view of a portion and its nearbyportion of a ROPS frame as a first alternative embodiment at which theback upper end of a pipe is coupled to the front upper end of anotherpipe.

FIG. 19 is a front cross-sectional view of a portion and its nearbyportion of a ROPS frame as a second alternative embodiment at which theback upper end of a pipe is coupled to the front upper end of anotherpipe.

FIG. 20 is a side cross-sectional view of a portion and its nearbyportion of a ROPS frame as a third alternative embodiment at which theback upper end of a pipe is coupled to the front upper end of anotherpipe.

FIG. 21 is a side cross-sectional view of a portion and its nearbyportion of a ROPS frame as a fifth alternative embodiment at which theback upper end of a pipe is coupled to the front upper end of anotherpipe.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIGS. 1 to 21 illustrate a multipurpose work vehicle provided with aroll-over protective structure (ROPS) frame 7 with joints 20 and 30.FIGS. 1 to 21 show “F” to indicate the forward direction, “B” toindicate the backward direction, “U” to indicate the upward direction,“D” to indicate the downward direction, “L” to indicate the leftwarddirection, and “R” to indicate the rightward direction.

Overall Configuration of Work Vehicle

As illustrated in FIG. 1 , the work vehicle includes a pair of left andright front wheels 1, a pair of left and right rear wheels 2, and a body3 supported by the front wheels 1 and the rear wheels 2. The body 3 isprovided with a pair of left and right front seats 4, a pair of left andright back seats 5, and a carrier box 6 backward of the back seats 5.

The work vehicle includes a ROPS frame 7 enclosing the front seats 4 andthe back seats 5. The work vehicle includes a windshield 8 (see FIG. 7 )at a front portion of the ROPS frame 7, a rear glass window 9 (see FIG.10 ) at a back portion of the ROPS frame 7, and a roof 33 at an upperportion of the ROPS frame 7. The work vehicle includes a pair of leftand right front doors 18 respectively at left front and right frontportions of the ROPS frame 7 and a pair of left and right rear doors 19respectively at left back and right back portions of the ROPS frame 7.

Overall Configuration of ROPS Frame

As illustrated in FIGS. 1 to 4 , the ROPS frame 7 includes a pair ofleft and right pipes 10 each in the shape of a channel in a side view, apair of left and right pipes 11 each angled in a side view, a pair ofleft and right pipes 12 each angled in a side view, a pair of left andright frame members 13, and a frame member 14.

The ROPS frame 7 includes (i) a pair of left and right front joints 20each coupling the front upper end of the corresponding pipe 10 to thefront lower end of the corresponding pipe 11, (ii) a frame member 15extending between and coupled to the front joints 20, and (iii) aplate-shaped frame member 17 extending between and coupled to the pipes11.

The ROPS frame 7 includes a pair of left and right rear joints 30 eachcoupling the back upper end of the corresponding pipe 10 to the backlower end of the corresponding pipe 12. The pipes 11 each have a backupper end coupled to the front upper end of the corresponding pipe 12.The ROPS frame 7 includes (i) a frame member 16 and a plate-shaped framemember 23 each extending between and coupled to the pipes 12 and (ii) apair of left and right handles 24 coupled to the respective pipes 12 anddesigned for use by a person to get in and out of the work vehicle.

The frame members 13 each extend in the up-down direction to be coupledto (i) an intermediate portion of the corresponding pipe 10 in thefront-back direction and (ii) that portion at which the back upper endof the corresponding pipe 11 is coupled to the front upper end of thecorresponding pipe 12. The ROPS frame 7 includes a pair of left andright handles 24 coupled to the respective pipes 13 and designed for useby a person to get in and out of the work vehicle.

The frame member 14 extends in the left-right direction to be coupled to(i) that portion at which the back upper end of the right pipe 11 iscoupled to the front upper end of the right pipe 12 and (ii) thatportion at which the back upper end of the left pipe 11 is coupled tothe front upper end of the left pipe 12.

The windshield 8 (see FIG. 7 ) is attached to and surrounded by thepipes 11 and the frame members 15 and 17. The rear glass window 9 (seeFIG. 10 ) is attached to the frame member 23 in such a manner as to becapable of being opened and closed in the front-back direction.

The front doors 18 are each attached to the corresponding frame member13 with use of hinges 25 in such a manner as to be capable of beingopened and closed. The rear doors 19 are each attached to thecorresponding pipes 10 and 12 with use of hinges 25 in such a manner asto be capable of being opened and closed.

The ROPS frame 7, as described above, includes pipes 10, 11, and 12 andframe members 13 to 17 and 23. The pipes 10 are coupled to the body 3.

Cross-Sectional Shapes of Pipes

As illustrated in FIGS. 2, 3, 14, and 15 , each pipe 11 has a pair ofsealing surfaces 11 a and 11 b each angled in cross section and oppositeto each other in a cross-sectional view.

Each pipe 11 also has a pair of non-sealing surfaces 11 c and 11 dopposite to each other in a cross-sectional view and each disposedbetween the sealing surfaces 11 a and 11 b. The sealing surfaces 11 aand 11 b and the non-sealing surfaces 11 c and 11 d extend along theentire length of the pipe 11.

As illustrated in FIGS. 2 and 7 to 9 , each pipe 10 has a pair ofsealing surfaces 10 a and 10 b and a pair of non-sealing surfaces 10 cand 10 d similarly to the pipes 11. The sealing surfaces 10 a and 10 band the non-sealing surfaces 10 c and 10 d extend along the entirelength of the pipe 10. The pipes 10 each have a cross-sectional shapeidentical to that of each pipe 11 (see FIGS. 14 and 15 ).

As illustrated in FIGS. 2, 3, 14, and 15 , each pipe 12 has a pair ofsealing surfaces 12 a and 12 b and a pair of non-sealing surfaces 12 cand 12 d similarly to the pipes 11. The sealing surfaces 12 a and 12 band the non-sealing surfaces 12 c and 12 d extend along the entirelength of the pipe 12. The pipes 12 each have a cross-sectional shapeidentical to that of each pipe 11 (see FIGS. 14 and 15 ).

As illustrated in FIGS. 2, 3, and 4 , the frame members 13, 15, and 16each have a rectangular cross section, while the frame member 14 has achannel-shaped cross section.

How Pipes are Related to Windshield, Front Doors, and Rear Doors

As illustrated in FIGS. 2, 5, and 6 , the ROPS frame 7 is configuredsuch that the respective sealing surfaces 10 a, 11 a, and 12 a of thepipes 10, 11, and 12 on each side are continuous with one another andface outward.

As illustrated in FIGS. 1 and 7 , each front door 18 has an outer edgeprovided with a rubber sealer 26 attached thereto. Closing the frontdoor 18 brings the sealer 26 into contact with the respective sealingsurfaces 10 a and 11 a of the corresponding pipes 10 and 11 and thecorresponding frame member 13 (see FIG. 4 ).

As illustrated in FIGS. 1 and 10 , each rear door 19 has an outer edgeprovided with a rubber sealer 27 attached thereto. Closing the rear door19 brings the sealer 27 into contact with the respective sealingsurfaces 10 a and 12 a of the corresponding pipes 10 and 12 and thecorresponding frame member 13 (see FIG. 4 ).

As illustrated in FIGS. 5 and 7 , the windshield 8 has an outer edgeprovided with a rubber sealer 28 attached thereto. The windshield 8 isattached to and surrounded by the pipes 11 and the frame members 15 and17 in such a manner that the sealer 28 is in contact with the respectivesealing surfaces 11 b of the pipes 11 and the frame members 15 and 17(see FIG. 4 ).

As illustrated in FIGS. 6 and 10 , the rear glass window 9 has an outeredge provided with a rubber sealer 29 attached thereto. Closing the rearglass window 9 brings the sealer 29 into contact with the respectivesealing surfaces 10 b and 12 b of the pipes 10 and 12 on each side andthe frame member 23 (see FIG. 4 ).

The roof 33 (see FIG. 1 ) has an outer edge provided with a rubbersealer (not shown in the drawings) attached thereto. As illustrated inFIGS. 5 and 6 , the roof 33 is attached to and disposed between thepipes 11 and 12 in such a manner that the sealer is in contact with therespective sealing surfaces 11 b of the pipes 11 and the respectivesealing surfaces 12 b of the pipes 12.

Configuration of Front Joints

As illustrated in FIGS. 1 to 4 , each front joint 20, which couples thefront upper end of the corresponding pipe 10 to the front lower end ofthe corresponding pipe 11, includes a first coupling section 21 and asecond coupling section 22.

As illustrated in FIGS. 5 to 9 , the first coupling section 21 includesa first sealing portion 21 a and a first non-sealing portion 21 b. Thefirst coupling section 21 also has, between the first sealing portion 21a and the first non-sealing portion 21 b, a first contact surface 21 dwith a depression 21 e. The first coupling section 21 includes acoupling portion 21 c with a bent shape in a side view. The couplingportion 21 c includes a third sealing portion 21 f, a third non-sealingportion 21 h, and an attachment portion 21 g.

The second coupling section 22 includes a second sealing portion 22 a, asecond non-sealing portion 22 b, and a coupling portion 22 c. The secondcoupling section 22 has, between the second sealing portion 22 a and thesecond non-sealing portion 22 b, a second contact surface 22 d with aprotrusion 22 e.

As illustrated in FIG. 7 , placing the first coupling section 21 and thesecond coupling section 22 on each other brings the first contactsurface 21 d into contact with the second coupling section 22 and thesecond contact surface 22 d into contact with the first coupling section21. The protrusion 22 e, which is at the second contact surface 22 d, istriangular in cross section and protrudes toward the first contactsurface 21 d in a cross-sectional view.

The depression 21 e, which is at the first contact surface 21 d, istriangular in cross section and receives the protrusion 22 e in across-sectional view. The depression 21 e is a portion of the firstcontact surface 21 d which portion is depressed toward the firstnon-sealing portion 21 b in a cross-sectional view.

Coupling of Front Joints

As illustrated in FIGS. 5 to 9 , the coupling portion 21 c is coupled tothe front upper end of the corresponding pipe 10 as a first pipe; theattachment portion 21 g is coupled to the frame member 15; and thecoupling portion 22 c is coupled to the front lower end of thecorresponding pipe 11 as a second pipe.

With the first coupling section 21 coupled to the corresponding pipe 10,the first non-sealing portion 21 b is continuous with the non-sealingsurface 10 d of the pair of non-sealing surfaces 10 c and 10 d of thepipe 10; the third sealing portion 21 f of is continuous with thesealing surface 10 a of the pair of sealing surfaces 10 a and 10 b ofthe pipe 10; and the third non-sealing portion 21 h is continuous withthe non-sealing surface 10 c of the pair of non-sealing surfaces 10 cand 10 d of the pipe 10.

With the second coupling section 22 coupled to the corresponding pipe11, the second sealing portion 22 a is continuous with the sealingsurface 11 a of the pair of sealing surfaces 11 a and 11 b of the pipe11; and the second non-sealing portion 22 b is continuous with thenon-sealing surface 11 c of the pair of non-sealing surfaces 11 c and 11d of the pipe 11.

With the first coupling section 21 of each joint 20 coupled to thecorresponding pipe 10 and the second coupling section 22 thereof coupledto the corresponding pipe 11 as described under “Configuration of FrontJoints” above, the first coupling section 21 (specifically, the firstcontact surface 21 d) and the second coupling section 22 (specifically,the second contact surface 22 d) are placed on each other as illustratedin FIGS. 7 and 8 .

With the first coupling section 21 and the second coupling section 22placed on each other, the protrusion 22 e is in the depression 21 e. Thefirst coupling section 21 and the second coupling section 22 are coupledto each other with use of bolts 34.

In a cross-sectional view, the bolts 34 in the above state each extendthrough the protrusion 22 e and the depression 21 e, obliquely cross thefirst contact surface 21 d and the second contact surface 22 d, and areeach in contact with the first non-sealing portion 21 b and the secondnon-sealing portion 22 b.

As described above, the joints 20 are each configured such that couplingthe first coupling section 21 and the second coupling section 22 to eachother results in the pipes 10 and 11 being coupled to each other withuse of the joint 20 (namely, the first coupling section 21 and thesecond coupling section 22) in such a manner that the front upper endand the front lower end face each other.

Positional Relationships Between Front Joints and Pipes

As illustrated in FIGS. 5 to 7 and 9 , with the first coupling section21 and the second coupling section 22 of each joint 20 coupled to eachother, the first coupling section 21, the second coupling section 22,and the corresponding pipes 10 and 11 are positionally related to oneanother as described below.

With the first coupling section 21 coupled to the second couplingsection 22, the third sealing portion 21 f is continuous with the secondsealing portion 22 a.

As described under “Coupling of Front Joints” above, the third sealingportion 21 f is continuous with the sealing surface 10 a of the pair ofsealing surfaces 10 a and 10 b of the corresponding pipe 10; and thesecond sealing portion 22 a is continuous with the sealing surface 11 aof the pair of sealing surfaces 11 a and 11 b of the corresponding pipe11.

This allows the sealing surface 10 a of the pipe 10 to be continuouswith the sealing surface 11 a of the pipe 11 with use of the thirdsealing portion 21 f and the second sealing portion 22 a.

As described under “How Pipes Are Related to Windshield, Front Doors,and Rear Doors” above, closing each front door 18 brings the sealer 26into contact with the respective sealing surfaces 10 a and 11 a of thecorresponding pipes 10 and 11 and the outer surface of the correspondingframe member 13. In this state, the sealer 26 is also in contact withthe third sealing portion 21 f and the second sealing portion 22 a.

Coupling the first coupling section 21 to the second coupling section 22results in the first sealing portion 21 a being continuous with thesealing surface 11 b of the pair of sealing surfaces 11 a and 11 b ofthe corresponding pipe 11.

When the sealer 28 of the windshield 8 is in contact with the respectivesealing surfaces 11 b of the pipes 11 as described under “How Pipes AreRelated to Windshield, Front Doors, and Rear Doors” above, the sealer 28is also in contact with the first sealing portion 21 a.

With the first coupling section 21 coupled to the second couplingsection 22, the third non-sealing portion 21 h is continuous with thesecond non-sealing portion 22 b.

As described under “Coupling of Front Joints” above, the firstnon-sealing portion 21 b is continuous with the non-sealing surface 10 dof the pair of non-sealing surfaces 10 c and 10 d of the correspondingpipe 10; the third non-sealing portion 21 h is continuous with thenon-sealing surface 10 c of the pair of non-sealing surfaces 10 c and 10d of the pipe 10; and the second non-sealing portion 22 b is continuouswith the non-sealing surface 11 c of the pair of non-sealing surfaces 11c and 11 d of the pipe 11.

This allows the non-sealing surface 10 c of the pipe 10 to be continuouswith the non-sealing surface 11 c of the pipe 11 with use of the thirdnon-sealing portion 21 h and the second non-sealing portion 22 b, andalso allows the non-sealing surface 10 d of the pipe 10 to be continuouswith the non-sealing surface 11 d of the pipe 11 with use of the firstnon-sealing portion 21 b.

Configuration of Rear Joints

As illustrated in FIGS. 1 to 4 , each rear joint 30, which couples theback upper end of the corresponding pipe 10 to the back lower end of thecorresponding pipe 12, includes a first coupling section 31 and a secondcoupling section 32.

As illustrated in FIGS. 5, 6, and 10 to 12 , the first coupling section31 includes a first sealing portion 31 a, a first non-sealing portion 31b, and a coupling portion 31 c. The first coupling section 31 also has,between the first sealing portion 31 a and the first non-sealing portion31 b, a first contact surface 31 d with a depression 31 e.

The second coupling section 32 includes a second sealing portion 32 a, asecond non-sealing portion 32 b, and a coupling portion 32 c. The secondcoupling section 32 has, between the second sealing portion 32 a and thesecond non-sealing portion 32 b, a second contact surface 32 d with aprotrusion 32 e.

As illustrated in FIG. 10 , placing the first coupling section 31 andthe second coupling section 32 on each other brings the first contactsurface 31 d into contact with the second coupling section 32 and thesecond contact surface 32 d into contact with the first coupling section31. The protrusion 32 e, which is at the second contact surface 32 d, istriangular in cross section and protrudes toward the first contactsurface 31 d in a cross-sectional view.

The depression 31 e, which is at the first contact surface 31 d, istriangular in cross section and receives the protrusion 32 e in across-sectional view. The depression 31 e is a portion of the firstcontact surface 31 d which portion is depressed toward the firstnon-sealing portion 31 b in a cross-sectional view.

Coupling of Rear Joints

As illustrated in FIGS. 5, 6, and 10 to 12 , the coupling portion 31 cis coupled to the back upper end of the corresponding pipe 10 as a firstpipe; and the coupling portion 32 c is coupled to the back lower end ofthe corresponding pipe 12 as a second pipe.

With the first coupling section 31 coupled to the corresponding pipe 10,the first sealing portion 31 a is continuous with the sealing surface 10a of the pair of sealing surfaces 10 a and 10 b of the pipe 10; and thefirst non-sealing portion 31 b is continuous with the non-sealingsurface 10 d of the pair of non-sealing surfaces 10 c and 10 d of thepipe 10.

With the second coupling section 32 coupled to the corresponding pipe12, the second sealing portion 32 a is continuous with the sealingsurface 12 b of the pair of sealing surfaces 12 a and 12 b of the pipe12; and the second non-sealing portion 32 b is continuous with thenon-sealing surface 12 c of the pair of non-sealing surfaces 12 c and 12d of the pipe 12.

With the first coupling section 31 of each joint 30 coupled to thecorresponding pipe 10 and the second coupling section 32 thereof coupledto the corresponding pipe 12 as described under “Configuration of RearJoints” above, the first coupling section 31 (specifically, the firstcontact surface 31 d) and the second coupling section 32 (specifically,the second contact surface 32 d) are placed on each other as illustratedin FIGS. 10 and 11 .

With the first coupling section 31 and the second coupling section 32placed on each other, the protrusion 32 e is in the depression 31 e. Thefirst coupling section 31 and the second coupling section 32 are coupledto each other with use of bolts 34.

In a cross-sectional view, the bolts 34 in the above state each extendthrough the protrusion 32 e and the depression 31 e, obliquely cross thefirst contact surface 31 d and the second contact surface 32 d, and areeach in contact with the first non-sealing portion 31 b and the secondnon-sealing portion 32 b.

As described above, the joints 30 are each configured such that couplingthe first coupling section 31 and the second coupling section 32 to eachother results in the pipes 10 and 12 being coupled to each other withuse of the joint 30 (namely, the first coupling section 31 and thesecond coupling section 32) in such a manner that the back upper end andthe back lower end face each other.

Positional Relationships Between Rear Joints and Pipes

As illustrated in FIGS. 5, 6, 10, and 12 , with the first couplingsection 31 and the second coupling section 32 of each joint 30 coupledto each other, the first coupling section 31, the second couplingsection 32, and the corresponding pipes 10 and 12 are positionallyrelated to one another as described below.

Coupling the first coupling section 31 to the second coupling section 32results in the first sealing portion 31 a being continuous with thesealing surface 12 a of the pair of sealing surfaces 12 a and 12 b ofthe corresponding pipe 12.

As described under “Coupling of Rear Joints” above, the first sealingportion 31 a is continuous with the sealing surface 10 a of the pair ofsealing surfaces 10 a and 10 b of the corresponding pipe 10.

This allows the sealing surface 10 a of the pipe 10 to be continuouswith the sealing surface 12 a of the corresponding pipe 12 with use ofthe first sealing portion 31 a.

When, as a result of closing each rear door 19, the sealer 27 thereof isin contact with the respective sealing surfaces 10 a and 12 a of thecorresponding pipes 10 and 12 as described under “How Pipes Are Relatedto Windshield, Front Doors, and Rear Doors” above, the sealer 27 is alsoin contact with the first sealing portion 31 a.

Coupling the first coupling section 31 to the second coupling section 32results in the second sealing portion 32 a being continuous with thesealing surface 10 b of the pair of sealing surfaces 10 a and 10 b ofthe corresponding pipe 10.

As described under “Coupling of Rear Joints” above, the second sealingportion 32 a is continuous with the sealing surface 12 b of the pair ofsealing surfaces 12 a and 12 b of the corresponding pipe 12.

This allows the sealing surface 10 b of the corresponding pipe 10 to becontinuous with the sealing surface 12 b of the pipe 12 with use of thesecond sealing portion 32 a.

When, as a result of closing rear glass window 9, the sealer 29 thereofis in contact with the respective sealing surfaces 10 b and 12 b of thepipes 10 and 12 on each side as described under “How Pipes Are Relatedto Windshield, Front Doors, and Rear Doors” above, the sealer 29 is alsoin contact with the second sealing portion 32 a.

Coupling the first coupling section 31 to the second coupling section 32results in (i) the first non-sealing portion 31 b being continuous withthe non-sealing surface 12 d of the corresponding pipe 12 and (ii) thesecond non-sealing portion 32 b being continuous with the non-sealingsurface 10 c of the corresponding pipe 10.

As described under “Coupling of Rear Joints” above, the firstnon-sealing portion 31 b is continuous with the non-sealing surface 10 dof the pair of non-sealing surfaces 10 c and 10 d of the correspondingpipe 10; and the second non-sealing portion 32 b is continuous with thenon-sealing surface 12 c of the pair of non-sealing surfaces 12 c and 12d of the corresponding pipe 12.

This allows the non-sealing surface 10 c of the pipe 10 to be continuouswith the non-sealing surface 12 c of the pipe 12 with use of the secondnon-sealing portion 32 b, and also allows the non-sealing surface 10 dof the pipe 10 to be continuous with the non-sealing surface 12 d of thepipe 12 with use of the first non-sealing portion 31 b of the firstcoupling section 31.

How Pipes and Frame Members of ROPS Frame are Structurally Coupled

The description below deals with that portion at which are coupled toone another (i) the back upper end of each pipe 11 as a first pipe (onthe left side as an example; similar descriptions apply also to theright side), (ii) the front upper end of the corresponding pipe 12 as asecond pipe”, (iii) the upper end of the corresponding frame member 13as a first frame member, and (iv) the corresponding end of the framemember 14 as a second frame member.

As illustrated in FIGS. 2, 3, 5, 6, and 13 to 16 , the ROPS frame 7includes a plate-shaped first joint 41 and a plate-shaped second joint42. The first joint 41 is welded to the back upper end of the pipe 11and oriented orthogonally to the longitudinal direction of the upperportion of the pipe 11. The second joint 42 is welded to the front upperend of the pipe 12 and oriented orthogonally to the longitudinaldirection of the upper portion of the pipe 12.

The first and second joints 41 and 42 are placed on each other in such amanner that the back upper end of the pipe 11 and the front upper end ofthe pipe 12 face each other. The first and second joints 41 and 42 areprovided with bolts 35 extending therethrough and fastening the firstand second joints 41 and 42 to each other. The back upper end of thepipe 11 and the front upper end of the pipe 12 are thereby coupled toeach other with use of the first and second joints 41 and 42 and thebolts 35.

The frame member 13 extends in the up-down direction, which crosses therespective upper portions of the pipes 11 and 12. The frame member 13has an upper end facing the back upper end of the pipe 11 and the frontupper end of the pipe 12.

The frame member 14 extends in the left-right direction, which crossesthe respective upper portions of the pipes 11 and 12 and the upperportion of the frame member 13. The frame member 14 has a left (right)end facing the back upper end of the pipe 11 and the front upper end ofthe pipe 12.

The ROPS frame 7 includes a coupling member 36 (see FIG. 17 ) couplingto one another (i) the back upper end of the pipe 11, (ii) the frontupper end of the pipe 12, (iii) the upper end of the frame member 13,and (iv) the left (right) end of the frame member 14 as described under“Structure of Coupling Member”, “Coupling with Use of Coupling Member”,and “Coupling of Coupling Member” below.

Structure of Coupling Member

As illustrated in FIG. 17 , the coupling member 36 is in the form of abent plate. The coupling member 36 includes four coupling sections 36 a,36 b, 36 c, and 36 d and four connection sections 36 e, 36 f, 36 g, and36 h. The connection section 36 e extends between the coupling sections36 a and 36 c. The connection section 36 f extends between the couplingsections 36 b and 36 c. The connection section 36 g extends between thecoupling sections 36 a and 36 d. The connection section 36 h extendsbetween the coupling sections 36 b and 36 d.

The coupling member 36 is configured such that the coupling sections 36a and 36 b are each bent in the shape of a depression and are apart fromeach other with a space in-between and that the connection sections 36 eand 36 g are apart from the connection sections 36 f and 36 h with aspace in-between.

Coupling with Use of Coupling Member

As illustrated in FIGS. 13 to 17 , the upper end of the frame member 13is provided with a pair of collars 37 and 38 welded thereto, while theleft (right) end of the frame member 14 is coupled to the collar 37 withuse of a bolt 39. This results in coupling between the upper end of theframe member 13 and the left (right) end of the frame member 14.

The ROPS frame 7 includes a first auxiliary coupling member 43 and asecond auxiliary coupling member 44 each in the form of a bent plate.The first auxiliary coupling member 43 is welded to the back upper endof the pipe 11, while the second auxiliary coupling member 44 is weldedto the front upper end of the pipe 12.

The connection section 36 c is coupled to the collar 38 with use of abolt 40 to thereby be coupled to the upper end of the frame member 13.The connection section 36 d is coupled to the left (right) end of theframe member 14 with use of bolts 47.

With the back upper end of the pipe 11 fitted in the connection section36 a, the coupling section 36 a and the first auxiliary coupling member43 are provided with a bolt 45 extending therethrough and fastening theconnection section 36 a to the first auxiliary coupling member 43. Thisresults in the back upper end of the pipe 11 being coupled to theconnection section 36 a.

With the front upper end of the pipe 12 fitted in the connection section36 b, the coupling section 36 b and the second auxiliary coupling member44 are provided with a bolt 46 extending therethrough and fastening theconnection section 36 b to the second auxiliary coupling member 44. Thisresults in the front upper end of the pipe 12 being coupled to theconnection section 36 b.

The coupling sections 36 a and 36 b are coupled respectively to the backupper end of the pipe 11 and to the front upper end of the pipe 12 insuch a manner that the coupling section 36 a and the first auxiliarycoupling member 43 cover the back upper end of the pipe 11 and that thecoupling section 36 b and the second auxiliary coupling member 44 coverthe front upper end of the pipe 12.

The first auxiliary coupling member 43 and the second auxiliary couplingmember 44 may alternatively be uncoupled respectively from the backupper end of the pipe 11 and from the front upper end of the pipe 12.

Coupling of Coupling Member

As described under “Structure of Coupling Member” and “Coupling with Useof Coupling Member” above and illustrated in FIGS. 13 to 17 , thecoupling sections 36 a and 36 c and the connection section 36 e arecoupled to the back upper end of the pipe 11 and the upper end of theframe member 13; and the coupling sections 36 b and 36 c and theconnection section 36 f are coupled to the front upper end of the pipe12 and the upper end of the frame member 13.

Further, the coupling sections 36 a and 36 d and the connection section36 g are coupled to the back upper end of the pipe 11 and the left(right) end of the frame member 14; and the coupling sections 36 b and36 d and the connection section 36 h are coupled to the front upper endof the pipe 12 and the left (right) end of the frame member 14.

As described under “Structure of Coupling Member” above, the couplingmember 36 is configured such that the coupling sections 36 a and 36 bare apart from each other and that the connection sections 36 e and 36 gare apart from the connection sections 36 f and 36 h. The left (right)end of the frame member 14 has an opening 14 a (see FIG. 5 ).

The back upper end of the pipe 11 and the front upper end of the pipe 12face each other at a portion (in other words, the first and secondjoints 41 and 42 and the bolts 35) that is (i) between the couplingsections 36 a and 36 b, (ii) between the connection sections 36 e and 36g and the connection sections 36 f and 36 h, and (iii) in the opening 14a.

First Alternative Embodiment

The back upper end of the pipe 11 and the front upper end of the pipe 12may be structurally coupled to each other with use of the first andsecond joints 41 and 42 as described below.

As illustrated in FIG. 18 , this embodiment includes a plate-shapedfirst joint 41 that is, with the back upper end of the pipe 11 facingthe front upper end of the pipe 12, placed on the non-sealing surface 11d (outer surface) of the back upper end of the pipe 11 and thenon-sealing surface 12 d (outer surface) of the front upper end of thepipe 12.

This embodiment also includes a plate-shaped second joint 42 placed onthe non-sealing surface 11 c (outer surface) of the back upper end ofthe pipe 11 and the non-sealing surface 12 c (outer surface) of thefront upper end of the pipe 12. The first and second joints 41 and 42are opposite to each other in a cross-sectional view of the pipes 11 and12.

This embodiment includes a first collar 51 that has a cylindrical shape,that is inside the back upper end of the pipe 11, and that is attachedto that portion of the non-sealing surface 11 d which faces the firstjoint 41 and to that portion of the non-sealing surface 11 c which facesthe second joint 42.

This embodiment includes a second collar 52 that has a cylindricalshape, that is inside the front upper end of the pipe 12, and that isattached to that portion of the non-sealing surface 12 d which faces thefirst joint 41 and to that portion of the non-sealing surface 12 c whichfaces the second joint 42.

This embodiment includes a first bolt 53 extending through the first andsecond joints 41 and 42 and the first collar 51 and fastening the firstand second joints 41 and 42 toward each other.

This embodiment includes a second bolt 54 extending through the firstand second joints 41 and 42 and the second collar 52 and fastening thefirst and second joints 41 and 42 toward each other.

The above configuration allows the back upper end of the pipe 11 and thefront upper end of the pipe 12 to be coupled to each other with use ofthe first and second joints 41 and 42 and the first and second bolts 53and 54.

In a case where the pipes 11 and 12 each have a circular cross-sectionalshape unlike in FIGS. 14 and 15 , the first and second joints 41 and 42may together be a cylinder. With this configuration, the cylinder has aportion as the first joint 41 and another portion as the second joint 42that is shifted in phase by 180 degrees from the first joint 41.

Second Alternative Embodiment

This embodiment is configured as described under “First AlternativeEmbodiment” above and illustrated in FIG. 18 , and includes framemembers 13 and 14 illustrated in FIGS. 13 to 16 as described below.

As illustrated in FIG. 19 , this embodiment is configured such that thefirst joint 41 includes a coupling section 41 a extending therefromdownward and coupled to the collar 38 (hence to the frame member 13)with use of a bolt 40 and that the second joint 42 includes a couplingsection 42 a extending therefrom laterally and coupled to the framemember 14 with use of bolts 47.

The frame member 13 is not provided with the collar 37 illustrated inFIGS. 14 and 15 , and is provided with an internally threaded boss 48welded to the upper end thereof. The frame member 14 is coupled to theboss 48 (hence to the frame member 13) with use of a bolt 39.

This configuration allows the first and second joints 41 and 42 toperform the function of the coupling member 36 illustrated in FIGS. 13to 17 , thereby eliminating the need to includes a separate couplingmember 36.

Third Alternative Embodiment

The back upper end of the pipe 11 and the front upper end of the pipe 12may be structurally coupled to each other with use of the first andsecond joints 41 and 42 as described below.

As illustrated in FIG. 20 , this embodiment includes a plate-shapedfirst joint 41 with a first portion welded to the inner surface(non-sealing surface 11 d) of the back upper end of the pipe 11 and asecond portion protruding from the back upper end of the pipe 11. Thisembodiment also includes a nut 49 welded to the inner surface of thesecond portion of the first joint 41.

This embodiment includes a plate-shaped second joint 42 with a firstportion welded to the inner surface (non-sealing surface 11 c) of theback upper end of the pipe 11 and a second portion protruding from theback upper end of the pipe 11. This embodiment also includes a nut 49welded to the inner surface of the second portion of the second joint42. The first and second joints 41 and 42 are opposite to each other ina cross-sectional view of the pipes 11 and 12.

The respective second portions of the first and second joints 41 and 42are inserted in the front upper end of the pipe 12, so that the backupper end of the pipe 11 and the front upper end of the pipe 12 faceeach other. This embodiment includes two bolts 50 screwed in therespective nuts 49 on the first and second joints 41 and 42 from outwardof the front upper end of the pipe 12 and fastening the pipe 12 to thefirst and second joints 41 and 42.

The above configuration allows the back upper end of the pipe 11 and thefront upper end of the pipe 12 to be coupled to each other with use ofthe first and second joints 41 and 42, the bolts 50, and the nuts 49.

Fourth Alternative Embodiment

This embodiment is configured as described under “Third AlternativeEmbodiment” above and illustrated in FIG. 20 , and is altered such thatthe first and second joints 41 and 42 have respective first portionseach welded to the inner surfaces (non-sealing surfaces 12 d and 12 c)of the front upper end of the pipe 12 and respective second portionseach protruding from the front upper end of the pipe 12. With thisconfiguration, the pipe 12 serves as the first pipe, whereas the pipe 11serves as the second pipe.

In a case where the first joint 41 has a first portion coupled to theinner surface (non-sealing surface 11 d) of the back upper end of thepipe 11 as described under “Third Alternative Embodiment” above andillustrated in FIG. 20 , the second joint 42 may have a first portioncoupled to the inner surface of the front upper end of the pipe 12 and asecond portion protruding from the front upper end of the pipe 12.

In a case where the pipes 11 and 12 each have a circular cross-sectionalshape unlike in FIGS. 14 and 15 , this embodiment may include, inaddition to the first and second joints 41 and 42, a third joint and anut as well as a fourth joint and a nut.

In a case where the pipes 11 and 12 each have a circular cross-sectionalshape unlike in FIGS. 14 and 15 , the first and second joints 41 and 42may together be a cylinder. With this configuration, the cylinder has aportion as the first joint 41 and other portions as the second joint 42and the third and fourth joints that are shifted in phase from the firstjoint 41.

Fifth Alternative Embodiment

In a case where the first and second joints 41 and 42 cannot be providedto extend along the entire circumference of the respective ends of thepipes 11 and 12 as illustrated in FIGS. 13 to 16 , the back upper end ofthe pipe 11 and the front upper end of the pipe 12 may be structurallycoupled to each other with use of the first and second joints 41 and 42as described below.

As illustrated in FIG. 21 , this embodiment includes a plate-shapedfirst joint 41 and a plate-shaped second joint 42 each angled in crosssection and having an area of about a quadrant of the cross section ofthe pipes 11 and 12. The first and second joints 41 and 42 are welded tothe respective outer surfaces of the respective ends of the pipes 11 and12 and oriented orthogonally to the longitudinal direction of the pipes11 and 12.

This embodiment includes a plate-shaped third joint 55 extending in thelongitudinal direction of the pipes 11 and 12. The third joint 55 has afirst portion welded to the outer surface of the back upper end of thepipe 11 and a second portion protruding from the back upper end of thepipe 11.

This embodiment also includes a plate-shaped fourth joint 56 extendingin the longitudinal direction of the pipes 11 and 12 and welded to theouter surface of the front upper end of the pipe 12.

The first and second joints 41 and 42 are placed on each other in such amanner that the back upper end of the pipe 11 and the front upper end ofthe pipe 12 face each other. The first and second joints 41 and 42 areprovided with bolts 35 extending therethrough and fastening the firstand second joints 41 and 42 to each other.

The second portion of the third joint 55 and the fourth joint 56 areplaced on each other. The third and fourth joints 55 and 56 are providedwith a bolt 57 extending therethrough and fastening the third and fourthjoints 55 and 56 to each other.

The back upper end of the pipe 11 and the front upper end of the pipe 12are thereby coupled to each other with use of the first and secondjoints 41 and 42, the third and fourth joints 55 and 56, and the bolts35 and 57.

This embodiment may be altered such that the third joint 55 is coupledto the pipe 12 and that the fourth joint 56 is coupled to the pipe 11.

Sixth Alternative Embodiment

FIGS. 13 to 16 and the first to fourth alternative embodiments eachinvolve a first joint 41 structurally coupled to a second joint 42. Thiscoupling structure may be applied to the coupling between the frontupper end of the pipe 10 and the front lower end of the pipe 11 and/orto the coupling between the back upper end of the pipe 10 and the backlower end of the pipe 12.

FIGS. 7 to 12 each illustrate a joint 20 structurally coupled to a joint30. This coupling structure may be applied to the coupling between theback upper end of the pipe 11 and the front upper end of the pipe 12.

The present invention is applicable to not only multipurpose workvehicles but also, for example, riding-type mowers and tractors.

The invention claimed is:
 1. A roll-over protective structure (ROPS)frame for a work vehicle, comprising: a plurality of pipes comprising: afirst pipe having a rear end; and a second pipe having a front endfacing the rear end of the first pipe, the rear end and the front endbeing disposed in an upper portion of the ROPS frame; a plate-shapedfirst joint coupled to the rear end of the first pipe and orientedorthogonally to a longitudinal direction of the pipes; a plate-shapedsecond joint coupled to the front end of the second pipe and orientedorthogonally to the longitudinal direction of the pipes, the secondjoint placed on the first joint; and a pair of bolts each extendingthrough the first and second joints and fastening the first and secondjoints to each other, the first pipe and the second pipe each have apair of recesses which are recessed toward an axial area of the pipe,the pair of recesses arranged opposite to each other across the axialarea, as viewed in the longitudinal direction, the pair of recessesincludes a first recess positioned upward relative to the axial area andlaterally inward relative to the axial area, and a second recesspositioned downward relative to the axial area and laterally outwardrelative to the axial area, and the pair of bolts includes a first boltadjacent to the first recess, and a second bolt adjacent to the secondrecess.
 2. A work vehicle, comprising: a ROPS frame according toclaim
 1. 3. A roll-over protective structure (ROPS) comprising: aplurality of pipes comprising: a first pipe having an end; and a secondpipe having an end facing the end of the first pipe; a plate-shapedfirst joint coupled to the end of the first pipe and orientedorthogonally to a longitudinal direction of the pipes; a plate-shapedsecond joint coupled to the end of the second pipe and orientedorthogonally to the longitudinal direction of the pipes, the secondjoint placed on the first joint; a bolt extending through the first andsecond joints and fastening the first and second joints to each other; afirst frame member oriented in a direction crossing the first and secondpipes and having an end facing the respective ends of the first andsecond pipes; and a coupling member coupled to the end of the first pipeand the end of the first frame member and coupled to the end of thesecond pipe and the end of the first frame member.
 4. The ROPS frameaccording to claim 3, further comprising: a second frame member orientedin a direction crossing the first and second pipes and the first framemember and having an end facing the respective ends of the first andsecond pipes, and wherein the coupling member is further coupled to theend of the first pipe and the end of the second frame member and coupledto the end of the second pipe and the end of the second frame member. 5.The ROPS frame according to claim 4, wherein: the end of the first framemember and the end of the second frame member are coupled to each other.6. The ROPS frame according to claim 3, wherein: the coupling member iscoupled to the end of the first pipe at a first coupling portion apartfrom a second coupling portion at which the coupling member is coupledto the end of the second pipe, and the respective ends of the first andsecond pipes face each other at a portion between the first couplingportion and the second coupling portion.
 7. The ROPS frame according toclaim 3, wherein: the coupling member is coupled to the end of the firstpipe with: the coupling member placed on an outer surface of the end ofthe first pipe; and a first auxiliary coupling member placed on theouter surface of the end of the first pipe and coupled to the couplingmember, and the coupling member is coupled to the end of the second pipewith: the coupling member placed on an outer surface of the end of thesecond pipe; and a second auxiliary coupling member placed on the outersurface of the end of the second pipe and coupled to the couplingmember.
 8. A roll-over protective structure (ROPS) frame for a workvehicle, comprising: a plurality of pipes comprising: a first pipehaving a rear end; and a second pipe having a front end facing the rearend of the first pipe, the rear end and the front end disposed in anupper portion of the ROPS frame; a plate-shaped first joint coupled tothe rear end of the first pipe and oriented orthogonally to alongitudinal direction of the pipes; a plate-shaped second joint coupledto the front end of the second pipe and oriented orthogonally to thelongitudinal direction of the pipes, the second joint placed on thefirst joint; and a pair of bolts each extending through the first andsecond joints and fastening the first and second joints to each other,wherein the pair of bolts are disposed in respective end portions of avirtual line in the first joint and the second joint, the virtual linebeing a longest line across the joint and passing an axial area of thepipe, as viewed in the longitudinal direction of the pipes, and whereinthe pair of bolts includes a first bolt positioned upward relative tothe axial area and laterally inward relative to the axial area as viewedin the longitudinal direction of the pipes, and a second bolt positioneddownward relative to the axial area and laterally outward relative theaxial area as viewed in the longitudinal direction of the pipes.